Bypasses are, for example, used in gas turbines to bleed compressor air away from the burners of the gas turbine or from the compressor to the turbine section, in particular for active clearance control. To control the air flow from the burners or to the turbine section, respectively, control valves are present in the bypasses. A gas turbine with bypasses used for active clearance control is, for example, disclosed in SE 9801821-1.
Up to now typically servo-controlled valves have been used for controlling the air flow through the bypasses. However, those servo-controlled valves comprise moving parts which require servos and signals to operate. This adds cost and may reduce reliability of the valves.